A high-voltage cable white spot detection method and device, electronic equipment and storage medium

Abstract

The application discloses a high-voltage cable white spot detection method and device, electronic equipment and storage medium, and comprises the following steps: establishing a circular thermal circuit model of the cable according to the structure parameters of the outer structure of each layer of the cable, the circular thermal circuit model is the cross section of the cable, the cross section is divided into a plurality of sectorial elements, each sectorial element comprises a plurality of thermal resistance branches extending from the conductor to the outer sheath, and each thermal resistance branch comprises a structure thermal resistance corresponding to the outer structure; at least one thermal resistance branch further comprises a white spot thermal resistance; for each thermal resistance branch, the thermal resistance value of the structure thermal resistance on each thermal resistance branch is calculated according to the arc and structure parameters of the sectorial element; the cable surface temperature corresponding to each thermal resistance branch, the conductor temperature of the conductor and the load current value of the conductor are measured; the thermal resistance value of the white spot thermal resistance is calculated according to the above data, and whether the white spot exists and the position of the white spot are determined. The white spot can be detected in the early stage of the generation of the white spot, and the white spot is prevented from further expanding.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power grid maintenance, and particularly relates to a high-voltage cable white spot detection method and device, electronic equipment and a storage medium. BACKGROUND

[0002] High-voltage cross-linked polyethylene cables have strong current-carrying capacity, good stability and wide application. However, as the running time of the high-voltage cable increases, buffer layer ablation faults occur, which occur between the wrinkle aluminum sheath of the high-voltage cable body and the outer semi-conductive shielding (insulation layer), and are characterized by the formation of "white spots" on the buffer layer, the outer semi-conductive shielding layer and the inner surface of the aluminum sheath. In order to solve the problem of white spots in the buffer layer of the wrinkle aluminum sheath cable after a certain period of operation, cable manufacturers have begun to use smooth aluminum sheaths to replace the wrinkle aluminum sheath manufacturing scheme and have begun to operate. However, even with smooth aluminum sheaths, the existing cable manufacturers' degassing operation is not standardized or the degassing time is not enough, which still leads to the generation of water vapor plus the inevitable potential difference, and the buffer layer still has the problem of white spots due to electrochemical corrosion. With the increase of the running time of the cable, the thickness of the white spot will change constantly due to the influence of the temperature and humidity of the laying environment, thereby greatly affecting the operation performance of the cable.

[0003] At present, the detection method for white spots mainly detects the position of the white spot through fault (white spot induced cable line fault) maintenance, but this will cause power loss, and usually only after the white spot fault is found does it have a great impact on the stable operation of the cable. There is no specific detection scheme for whether there is a white spot in the normally operating cable. Moreover, most of the research focuses on the repair method of the white spot and the detection of the discharge performance after repair, and no method for determining the position of the white spot has been given. SUMMARY

[0004] The present application provides a high-voltage cable white spot detection method to solve the problem of high-voltage cable white spot detection.

[0005] In a first aspect, the present application provides a high-voltage cable white spot detection method, the structure of the cable includes a conductor and a three-layer external structure, the external structure includes an insulation layer, a buffer layer and an outer sheath from inside to outside, the cross section of the external structure is annular, and the method comprises:

[0006] Obtaining the structure parameters of each layer of the external structure of the cable, the structure parameters including the inner diameter and the outer diameter of the external structure;

[0007] According to the structure parameter, a circular thermal circuit model of the cable is established, the circular thermal circuit model is a cross section of the cable, the cross section is divided into a plurality of sectorial microelements, each sectorial microelement includes a plurality of thermal resistance branches extending from the conductor to the outer sheath, and each thermal resistance branch includes a structure thermal resistance corresponding to the outer structure one by one; at least one thermal resistance branch further includes a white spot thermal resistance;

[0008] For each thermal resistance branch, the thermal resistance value of the structure thermal resistance on each thermal resistance branch is calculated according to the arc of the sectorial microelement and the structure parameter;

[0009] The cable surface temperature, the conductor temperature of the conductor and the load current value of the conductor corresponding to each thermal resistance branch are measured;

[0010] The cable full-line heat flow is calculated according to the conductor temperature and the load current value;

[0011] The thermal resistance value of the white spot thermal resistance is calculated according to the thermal resistance value of the structure thermal resistance, the cable surface temperature, the conductor temperature and the cable full-line heat flow;

[0012] Whether the white spot exists and the position of the white spot when the white spot exists are determined according to the thermal resistance value of the white spot thermal resistance.

[0013] In a second aspect, the present application provides a high-voltage cable white spot detection device, the structure of the cable includes a conductor and a three-layer outer structure, the outer structure includes an insulation layer, a buffer layer and an outer sheath from inside to outside, the cross section of the outer structure is annular, and the device includes:

[0014] A structure parameter acquisition module is configured to acquire structure parameters of each layer of the outer structure of the cable, the structure parameters including an inner diameter and an outer diameter of the outer structure;

[0015] A thermal circuit model construction module is configured to establish a circular thermal circuit model of the cable according to the structure parameters, the circular thermal circuit model being a cross section of the cable, the cross section being divided into a plurality of sectorial microelements, each sectorial microelement including a plurality of thermal resistance branches extending from the conductor to the outer sheath, and each thermal resistance branch including a structure thermal resistance corresponding to the outer structure one by one; at least one thermal resistance branch further includes a white spot thermal resistance;

[0016] A thermal resistance value calculation module is configured to calculate, for each thermal resistance branch, the thermal resistance value of the structure thermal resistance on each thermal resistance branch according to the arc of the sectorial microelement and the structure parameter;

[0017] A parameter measurement module is configured to measure the cable surface temperature, the conductor temperature of the conductor and the load current value of the conductor corresponding to each thermal resistance branch;

[0018] The cable heat flow calculation module is used to calculate the total heat flow of the cable based on the conductor temperature and the load current value.

[0019] The white spot thermal resistance calculation module is used to calculate the thermal resistance value of the white spot based on the thermal resistance value of the structure, the surface temperature of the cable, the conductor temperature, and the total heat flow of the cable.

[0020] The white spot qualitative module is used to determine whether a white spot exists and its location when it exists, based on the thermal resistance value of the white spot thermal resistance.

[0021] Thirdly, the present invention provides an electronic device, the electronic device comprising:

[0022] At least one processor; and

[0023] A memory communicatively connected to the at least one processor; wherein,

[0024] The memory stores a computer program that can be executed by the at least one processor, which enables the at least one processor to perform the high-voltage cable white spot detection method according to the first aspect of the present invention.

[0025] Fourthly, the present invention provides a computer-readable storage medium storing computer instructions that, when executed by a processor, implement the high-voltage cable white spot detection method described in the first aspect of the present invention.

[0026] The high-voltage cable white spot detection method provided by the embodiment of the application comprises the following steps: obtaining structure parameters of an outer structure of each layer of the cable, the structure parameters comprising an inner diameter and an outer diameter of the outer structure; establishing a circular thermal circuit model of the cable according to the structure parameters, the circular thermal circuit model being a cross section of the cable, the cross section being divided into a plurality of sectorial elements, each sectorial element comprising a plurality of thermal resistance branches extending from a conductor to an outer sheath, and each thermal resistance branch comprising a structure thermal resistance corresponding to the outer structure; at least one thermal resistance branch further comprising a white spot thermal resistance; for each thermal resistance branch, calculating a thermal resistance value of the structure thermal resistance on each thermal resistance branch according to an arc of the sectorial element to which the thermal resistance branch belongs and the structure parameters; measuring a cable surface temperature corresponding to each thermal resistance branch, a conductor temperature of the conductor and a load current value of the conductor; calculating a cable full-line heat flow according to the conductor temperature and the load current value, and calculating a thermal resistance value of the white spot thermal resistance according to the thermal resistance value of the structure thermal resistance, the cable surface temperature, the conductor temperature and the cable full-line heat flow; and determining whether the white spot exists and a position of the white spot when the white spot exists according to the thermal resistance value of the white spot thermal resistance. The sectorial element where the white spot is located is virtually constructed based on the thermal circuit model, and the parameters in each sectorial element are measured and calculated, and the thermal resistance value of the white spot is qualitatively calculated according to the Fourier heat transfer law and the thermal circuit model, so that whether the white spot exists and the position of the white spot when the white spot exists can be determined, the white spot can be detected in an early stage of generation of the white spot, the cable is repaired in time by filling a repair liquid, and a great influence on an operation performance of the cable caused by further expansion of the white spot is avoided.

[0027] It should be understood that the content described in this part is not intended to identify key or important features of the embodiments of the application, nor is it used to limit the scope of the application. Other features of the application will become apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0029] Figure 1 is a schematic diagram of a cross section structure of a cable provided by the embodiment of the application;

[0030] Figure 2 is a flowchart of a high-voltage cable white spot detection method provided by the embodiment of the application;

[0031] Figure 3 is a schematic diagram of a circular thermal circuit model provided by the embodiment of the application;

[0032] Figure 4is a structural schematic diagram of a high-voltage cable white spot detection device provided by an embodiment of the present application.

[0033] Figure 5 is a structural schematic diagram of an electronic device provided by an embodiment of the present application. DETAILED DESCRIPTION

[0034] In order for those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should fall within the scope of protection of the present application.

[0035] The present embodiment provides a high-voltage cable white spot detection method, which can be applied to the case of white spot detection of the insulation layer in the high-voltage cable. The method can be executed by a high-voltage cable white spot detection device, which can be realized in the form of hardware and / or software and can be configured in an electronic device. The cable in the present application is a high-voltage cable.

[0036] Figure 1 is a structural schematic diagram of a cross section of a cable provided by an embodiment of the present application, as shown in Figure 1 The structure of the cable includes a conductor A0 and a three-layer outer structure, and the outer structure includes, from the inside to the outside, an insulation layer A1, a buffer layer A2 and an outer sheath A2. The cross section of the outer structure is annular, and the cross section of the conductor A1 is circular.

[0037] Figure 2 is a flowchart of a high-voltage cable white spot detection method provided by an embodiment of the present application, as shown in Figure 2 The high-voltage cable white spot detection method includes:

[0038] S201, obtaining structure parameters of each layer of the outer structure of the cable.

[0039] The structure parameters include the inner diameter and the outer diameter of the outer structure. In addition, the thermal conductivity and the like are also included.

[0040] S202, establishing a circular thermal circuit model of the cable according to the structure parameters.

[0041] The circular thermal circuit model is the cross section of the cable, and the cross section is divided into a plurality of sectorial microelements. Each sectorial microelement includes a plurality of thermal resistance branches extending from the conductor to the outer sheath. Each thermal resistance branch includes a structure thermal resistance corresponding to the outer structure; and at least one thermal resistance branch further includes a white spot thermal resistance.

[0042] Figure 3This is a schematic diagram of a circular thermal path model. In one optional example, such as... Figure 3 As shown, the circular thermal path model represents the cross-section of the cable, consisting of one circle and three annular rings from the inside out. From the inside out, these are the conductor A0, insulation layer A1, buffer layer A2, and outer sheath A2. The cross-section is divided into multiple sector-shaped micro-elements. In this example, there are four sector-shaped micro-elements, each with the same radius of curvature (π / 2). Each of the four thermal resistance branches includes three structural thermal resistances corresponding to the insulation layer A1, buffer layer A2, and outer sheath A2. One of the thermal resistance branches also includes a white spot thermal resistance To. In this example, the outer sheath A2 is a smooth aluminum sheath.

[0043] In an optional example, such as Figure 3 As shown, there are four sector-shaped micro-elements, each with an radian θ of π / 2. The thermal resistance branch corresponding to the first sector-shaped micro-element includes the structural thermal resistance T. 11 T 12 T 13 The thermal resistance branch corresponding to the second sector element includes the structural thermal resistance T. 21 T 22 T 23 The thermal resistance branch corresponding to the third sector element includes the structural thermal resistance T. 31 T 32 T 33 The thermal resistance branch corresponding to the fourth sector element includes the structural thermal resistance T. 41 T 42 T 43 It also includes the white spot thermal resistance To; the white spot thermal resistance To is a preset virtual thermal resistance, that is, it is assumed that there is a white spot at this position and the white spot thermal resistance is To.

[0044] S203. For each thermal resistance branch, calculate the thermal resistance value of the structural thermal resistance on each thermal resistance branch based on the radii and structural parameters of the corresponding sector micro-element.

[0045] Specifically, the formula for calculating the thermal resistance value of the structure on each of the aforementioned thermal resistance branches is as follows:

[0046]

[0047] Where i is the index of the sector element to which the thermal resistance branch belongs, i = 1, 2…N s N s The number of the sector-shaped micro-elements; j is the number of layers of the external structure in the sector-shaped micro-elements, j = 1, 2…3, λ i Let r be the thermal conductivity, θ be the radian of the sector-shaped micro-element, and r be the thermal conductivity. jw Let r be the outer diameter of the external structure of the j-th layer. jnThe inner diameter of the outer structure of the jth layer, T ij The thermal resistance value of the thermal resistance of the jth layer of the outer structure corresponding to the ith sector microelement.

[0048] In an optional example, as shown in Figure 3 The number of sector microelements is 4, and the radian θ of each sector microelement is π / 2.

[0049] S204, measure the cable surface temperature, conductor temperature and load current value of the conductor corresponding to each thermal resistance branch.

[0050] In an optional embodiment, the temperature (cable surface temperature, conductor temperature of the conductor) is measured by a temperature sensor, and before measuring the cable surface temperature, conductor temperature and load current value of the conductor corresponding to each thermal resistance branch, it further includes: obtaining the reading deviation of the temperature sensor; judging whether the reading deviation of the temperature sensor is less than the preset deviation range; if yes, executing the step of measuring the cable surface temperature, conductor temperature and load current value of the conductor corresponding to each thermal resistance branch. In order to guarantee the accuracy of the temperature sensor measurement data, before using the sensor, connect the temperature sensor to the same experimental instrument to observe whether the reading deviates and the specific reading deviation. Replace the temperature sensor with large deviation in time to reduce the detection error.

[0051] Specifically, the corresponding cable surface temperature of the four thermal resistance branches can be directly measured, and in the circular thermal circuit model as shown in Figure 3 The corresponding surface temperatures of the four thermal resistance branches are θ1, θ2, θ3 and θ4, respectively. The conductor temperature needs to be detected by a temperature sensor after drilling a hole to the conductor along the trough of the aluminum sheath. c The load current value of the conductor can be measured by a current sensor.

[0052] S205, calculate the cable full-line heat flow according to the conductor temperature and the load current value.

[0053] The calculation formula of the cable full-line heat flow is as follows:

[0054] Q=I 2 R;

[0055] R=R0[1+α 20 (θ c -20)][1+y s +y p ];

[0056] Wherein, Q is the cable full-line heat flow, I is the load current value, R is the alternating current resistance value of the conductor, R0, α 20Let θ be the DC resistance and temperature coefficient of the conductor at 20℃. c For the temperature of the conductor, y s y p These are known skin effect factors and proximity effect factors.

[0057] The standard soft copper temperature coefficient is 0.00392K. The cable in this invention is a single-core cable, that is, the number of conductors is 1. For a single-core cable, the proximity effect factor is 0.

[0058] S206. Calculate the thermal resistance of the white spot based on the thermal resistance of the structure, the surface temperature of the cable, the conductor temperature, and the heat flow of the entire cable.

[0059] Specifically, the thermal resistance value of the white spot is calculated based on the thermal resistance value of the structure, the surface temperature of the cable, the conductor temperature, and the total heat flow of the cable, including:

[0060] Based on Fourier's heat transfer law and the circular thermal path model, a linear matrix formula is constructed. The linear matrix formula includes the structural thermal resistance, the cable surface temperature, the conductor temperature, the conductor temperature, the total heat flux of the cable, and the white spot thermal resistance. The thermal resistance value of the white spot thermal resistance is obtained by substituting the values ​​of the structural thermal resistance, the cable surface temperature, the conductor temperature, the conductor temperature, and the total heat flux of the cable into the linear matrix formula.

[0061] Fourier's law of heat transfer, also known as Fourier's law, describes that in the process of heat conduction, the amount of heat passing through a given cross section per unit time is directly proportional to the rate of temperature change and the cross section area in the direction perpendicular to that cross section, and the direction of heat transfer is opposite to the direction of temperature increase.

[0062] In an optional embodiment, in such a way Figure 3 In the circular thermal circuit model shown, the white spot thermal resistance is placed on the 4th thermal resistance branch, and the established linear matrix formula is:

[0063]

[0064] Where i is the index of the sector element to which the thermal resistance branch belongs, i = 1, 2…N s N s The number of the sector-shaped micro-elements; j is the number of layers of the external structure in the sector-shaped micro-elements, j = 1, 2, 3, λ i Let r be the thermal conductivity, θ be the radian of the sector-shaped micro-element, and r be the thermal conductivity. jw Let r be the outer diameter of the external structure of the j-th layer. jn Let T be the inner diameter of the external structure of the j-th layer. ijRi,j is the thermal resistance value of the thermal resistance corresponding to the jth layer of the outer structure in the ith sector microelement, and T0 is the thermal resistance value of the white spot thermal resistance.

[0065] Of course, the white spot thermal resistance can also be arranged on other thermal resistance branches, and in an optional embodiment, the white spot thermal resistance is arranged on the third thermal resistance branch, and in the circular thermal circuit model as shown in the figure, the linear matrix formula is established as follows: Figure 3

[0066]

[0067] In another optional embodiment, if the number of sector microelements is 5, the radian of each sector microelement is 2π / 5, the white spot thermal resistance is arranged on the third and fifth thermal resistance branches, and based on the process of establishing the circular thermal circuit model and the linear matrix formula in the above, the linear matrix formula is established as follows:

[0068]

[0069] In an optional embodiment, the calculation formula of the cable total heat flow is as follows:

[0070]

[0071] R = R0 [1 + α 20 (θ c - 20) ][1 + y s + y p ];

[0072] Wherein, Q is the cable total heat flow, I l is the current-carrying capacity of the conductor, R is the alternating current resistance value of the conductor, R0, α 20 is the direct current resistance and temperature coefficient of the conductor at 20℃, θ c is the temperature of the conductor, y s , y p is the known skin effect factor and proximity effect factor.

[0073] Wherein, the current-carrying capacity I l is the maximum current continuously and stably carried by the conductor at 90℃, and the temperature of the conductor θ c is 90℃. In this embodiment, the temperature of the conductor θ c can be directly obtained, without the need to punch from the surface of the cable to the surface of the conductor to detect the temperature of the conductor, so as to realize non-destructive detection of the white spot thermal resistance.

[0074] The standard soft copper temperature coefficient is 0.00392K, and the cable in the application is a single-core cable, that is, the number of conductors is 1. For single-core cables, the proximity effect factor is 0.

[0075] ​S207, determining whether the white spot exists according to the thermal resistance value of the white spot thermal resistance, and the position of the white spot when the white spot exists.

[0076] Specifically, it is determined whether the thermal resistance value of the white spot thermal resistance is greater than 0; if not, it is determined that the white spot does not exist; if yes, it is determined that the white spot exists; and the fan-shaped microelement where the white spot thermal resistance is located is taken as the position of the white spot.

[0077] That is, the hypothetical principle is adopted, it is assumed that the insulation layer on a certain thermal resistance branch still has a white spot thermal resistance, if the calculated white spot thermal resistance is 0, it is indicated that the white spot thermal resistance does not exist, if the calculated white spot thermal resistance is not 0 (greater than 0), it is indicated that the white spot thermal resistance indeed exists, and the insulation layer corresponding to the thermal resistance branch where the white spot thermal resistance is located is the position where the white spot fault occurs.

[0078] Further comprising: when the white spot exists, calculating the thickness of the white spot according to the thermal resistance value of the white spot thermal resistance. The thermal resistance value of the white spot thermal resistance is proportional to the thickness of the white spot, the greater the thermal resistance value of the white spot thermal resistance, the greater the thickness of the white spot.

[0079] The high-voltage cable white spot detection method provided by the embodiment of the application first acquires the structure parameters of the external structure of each layer of the cable, the structure parameters including the inner diameter and the outer diameter of the external structure; a circular thermal circuit model of the cable is established according to the structure parameters, the circular thermal circuit model is the cross section of the cable, the cross section is divided into a plurality of fan-shaped microelements, each fan-shaped microelement includes a plurality of thermal resistance branches extending from the conductor to the outer sheath, and each thermal resistance branch includes a structure thermal resistance corresponding to the external structure one by one; at least one thermal resistance branch further includes a white spot thermal resistance; for each thermal resistance branch, the thermal resistance value of the structure thermal resistance on each thermal resistance branch is calculated according to the radian of the corresponding fan-shaped microelement and the structure parameters; the surface temperature of the cable corresponding to each thermal resistance branch, the conductor temperature of the conductor and the load current value of the conductor are measured; the cable full-line heat flow is calculated according to the conductor temperature and the load current value, the thermal resistance value of the white spot thermal resistance is calculated according to the thermal resistance value of the structure thermal resistance, the surface temperature of the cable, the conductor temperature and the cable full-line heat flow; and whether the white spot exists and the position of the white spot when the white spot exists are determined according to the thermal resistance value of the white spot thermal resistance. Based on the thermal circuit model, the fan-shaped microelement where the white spot is located is virtually constructed, the parameters in each fan-shaped microelement are measured and calculated, and the thermal resistance value of the white spot is qualitatively calculated according to the Fourier heat transfer law combined with the thermal circuit model, so that whether the white spot exists and the position of the white spot when the white spot exists can be determined, the white spot can be detected in the early stage of the white spot, the cable can be repaired in time by filling the repair liquid, and the white spot is prevented from further expanding to greatly affect the operation performance of the cable.

[0080] Corresponding to the high-voltage cable white spot detection method in the present application, the present application further provides a high-voltage cable white spot detection device. The structure of the cable includes a conductor and a three-layer outer structure, and the outer structure includes an insulation layer, a buffer layer and an outer sheath from inside to outside, and the cross section of the outer structure is annular. Figure 4 A structural schematic diagram of a high-voltage cable white spot detection device provided for the third embodiment of the present application is shown in FIG. 3. Figure 4 As shown in the figure, the high-voltage cable white spot detection device includes:

[0081] A structure parameter acquisition module 401 is configured to acquire structure parameters of the outer structure of each layer of the cable, and the structure parameters include an inner diameter and an outer diameter of the outer structure.

[0082] A thermal circuit model construction module 402 is configured to establish a circular thermal circuit model of the cable according to the structure parameters, and the circular thermal circuit model is a cross section of the cable, the cross section is divided into a plurality of sectorial microelements, each sectorial microelement includes a plurality of thermal resistance branches extending from the conductor to the outer sheath, and each thermal resistance branch includes a structure thermal resistance corresponding to the outer structure; at least one thermal resistance branch further includes a white spot thermal resistance.

[0083] A thermal resistance value calculation module 403 is configured to calculate a thermal resistance value of the structure thermal resistance on each thermal resistance branch according to an arc of the sectorial microelement and the structure parameters.

[0084] A parameter measurement module 404 is configured to measure a cable surface temperature corresponding to each thermal resistance branch, a conductor temperature of the conductor and a load current value of the conductor.

[0085] A cable full-line heat flow calculation module 405 is configured to calculate a cable full-line heat flow according to the conductor temperature and the load current value.

[0086] A white spot thermal resistance calculation module 406 is configured to calculate a thermal resistance value of the white spot thermal resistance according to the thermal resistance value of the structure thermal resistance, the cable surface temperature, the conductor temperature and the cable full-line heat flow.

[0087] A white spot qualitative module 407 is configured to determine whether there is a white spot and a location of the white spot when the white spot exists according to the thermal resistance value of the white spot thermal resistance.

[0088] Optionally, the temperature is measured by a temperature sensor, and the high-voltage cable white spot detection device further includes:

[0089] A reading deviation acquisition module is configured to acquire a reading deviation of the temperature sensor.

[0090] A deviation judgment module is configured to judge whether the reading deviation of the temperature sensor is less than a preset deviation range; if yes, the content of the parameter measurement module 404 is executed.

[0091] Optionally, the white spot thermal resistance calculation module 406 comprises:

[0092] a linear matrix formula construction submodule, configured to construct a linear matrix formula based on the Fourier heat transfer law and the circular thermal circuit model, the linear matrix formula comprising the structural thermal resistance, the cable surface temperature, the conductor temperature, the conductor temperature, the cable full-line heat flow, and the white spot thermal resistance;

[0093] a white spot thermal resistance calculation submodule, configured to substitute the numerical values of the structural thermal resistance, the cable surface temperature, the conductor temperature, the conductor temperature, and the cable full-line heat flow into the linear matrix formula to obtain the thermal resistance value of the white spot thermal resistance.

[0094] Optionally, the white spot qualitative module 407 comprises:

[0095] a thermal resistance judgment submodule, configured to judge whether the thermal resistance value of the white spot thermal resistance is greater than 0;

[0096] a first qualitative submodule, configured to determine that there is no white spot if the thermal resistance value of the white spot thermal resistance is 0;

[0097] a second qualitative submodule, configured to determine that there is a white spot if the thermal resistance value of the white spot thermal resistance is greater than 0;

[0098] the position of the white spot thermal resistance is taken as the position of the white spot.

[0099] Optionally, the high-voltage cable white spot detection device further comprises:

[0100] a thickness detection module, configured to calculate the thickness of the white spot according to the thermal resistance value of the white spot thermal resistance when the white spot exists.

[0101] The high-voltage cable white spot detection device provided in the embodiments of the present application can perform the high-voltage cable white spot detection method provided in any of the embodiments of the present application, and has the corresponding function modules and beneficial effects of the execution method.

[0102] Figure 5 A structural schematic diagram of an electronic device 40 that can be used to implement embodiments of the present application is shown. The electronic device is intended to represent various forms of digital computers, such as laptops, desktops, tablets, personal digital assistants, servers, blade servers, mainframes, and other appropriate computers. The electronic device can also represent various forms of mobile devices, such as personal digital assistants, cellular telephones, smartphones, and other similar computing devices. The components shown here, their connections and relationships, and their functions, are meant to be examples only, and are not intended to limit the implementations of the present application described and / or claimed in this document.

[0103] like Figure 5 As shown, the electronic device 40 includes at least one processor 41 and a memory, such as a read-only memory (ROM) 42 or a random access memory (RAM) 43, communicatively connected to the at least one processor 41. The memory stores computer programs executable by the at least one processor. The processor 41 can perform various appropriate actions and processes based on the computer program stored in the ROM 42 or loaded into the RAM 43 from storage unit 48. The RAM 43 may also store various programs and data required for the operation of the electronic device 40. The processor 41, ROM 42, and RAM 43 are interconnected via a bus 44. An input / output (I / O) interface 45 is also connected to the bus 44.

[0104] Multiple components in electronic device 40 are connected to I / O interface 45, including: input unit 46, such as keyboard, mouse, etc.; output unit 47, such as various types of monitors, speakers, etc.; storage unit 48, such as disk, optical disk, etc.; and communication unit 49, such as network card, modem, wireless transceiver, etc. Communication unit 49 allows electronic device 40 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0105] Processor 41 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of processor 41 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. Processor 41 performs the various methods and processes described above, such as the white spot detection method for high-voltage cables.

[0106] In some embodiments, the high-voltage cable white spot detection method may be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 48. In some embodiments, part or all of the computer program may be loaded and / or installed on electronic device 40 via ROM 42 and / or communication unit 49. When the computer program is loaded into RAM 43 and executed by processor 41, one or more steps of the high-voltage cable white spot detection method described above may be performed. Alternatively, in other embodiments, processor 41 may be configured to perform the high-voltage cable white spot detection method by any other suitable means (e.g., by means of firmware).

[0107] The various embodiments of the systems and techniques described above can be implemented in digital electronic circuitry, integrated circuitry, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), a system on a chip (SOC), a complex programmable logic device (CPLD), computer hardware, firmware, software, and / or combinations thereof. These various embodiments can include implementation in one or more computer programs that are executable and / or interpretable on a programmable system including at least one programmable processor, which can be special or general purpose, coupled to receive data and instructions from, and to transmit data and instructions to, a storage system, at least one input device, and at least one output device.

[0108] Computer programs used to implement the processes of the application can be written in any combination of one or more programming languages. These computer programs can be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the computer program

[0109] In the context of the present application, a computer-readable storage medium can be a tangible medium that can contain or store computer programs for use by or in connection with an instruction execution system, apparatus, or device. Computer-readable storage media can include, but are not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium can be a machine-readable signal medium. More specific examples of the machine-readable storage medium will include one or more lines of a program of instructions in a transitory signal, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0110] To provide for interaction with a user, the systems and techniques described here can be implemented on an electronic device having a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user and a keyboard and a pointing device (e.g., a mouse or a trackball) by which the user can provide input to the electronic device. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form, including acoustic, speech, or tactile input.

[0111] The systems and techniques described here can be implemented in a computing system that includes a back end component (e.g., as a data server), or that includes a middleware component (e.g., an application server), or that includes a front end component (e.g., a user computer having a graphical user interface or a Web browser through which a user can interact with an implementation of the systems and techniques described here), or any combination of such back end, middleware, or front end components. The components of the system can be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0112] The computing system can include clients and servers. A client and server are generally remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other. A server can be a cloud server, also known as a cloud computing server or cloud host, which is a host product in the cloud computing service system, to solve the defects of large management difficulty and weak business scalability in traditional physical host and VPS service.

[0113] It should be understood that the various forms of flow shown above can be re-ordered, added to, or deleted from without departing from the scope of the present disclosure. For example, the steps recited in the present disclosure can be executed in parallel, executed in series, or executed in different orders, as long as the desired results of the technical solutions of the present disclosure are achieved, and the present disclosure is not limited herein.

[0114] The above detailed description does not constitute a limitation on the protection scope of the present application. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for detecting white spots in a high voltage cable, characterized in that, The structure of the cable comprises a conductor and a three-layer outer structure, the outer structure comprising, from inside to outside, an insulation layer, a buffer layer and an outer sheath, the cross section of the outer structure being annular, and the method comprising: obtaining structure parameters of each layer of the outer structure of the cable, the structure parameters comprising the inner diameter and the outer diameter of the outer structure; establishing a circular thermal circuit model of the cable according to the structure parameters, the circular thermal circuit model being a cross section of the cable, the cross section being divided into a plurality of sectorial elements, each sectorial element comprising a plurality of thermal resistance branches extending from the conductor to the outer sheath, and each thermal resistance branch comprising a structure thermal resistance corresponding to the outer structure; at least one thermal resistance branch further comprising a white spot thermal resistance; for each thermal resistance branch, calculating the thermal resistance value of the structure thermal resistance on each thermal resistance branch according to the arc of the sectorial element to which the thermal resistance branch belongs and the structure parameters; measuring the cable surface temperature corresponding to each thermal resistance branch, the conductor temperature of the conductor and the load current value of the conductor; calculating the total heat flow of the cable according to the conductor temperature and the load current value; calculating the thermal resistance value of the white spot thermal resistance according to the thermal resistance value of the structure thermal resistance, the cable surface temperature, the conductor temperature and the total heat flow of the cable; determining whether there is a white spot and the location of the white spot when there is a white spot according to the thermal resistance value of the white spot thermal resistance.

2. The high voltage cable whitening detection method of claim 1, wherein, The calculation formula of the thermal resistance value of the structure thermal resistance on each thermal resistance branch is as follows: Wherein, i is the serial number of the fan-shaped microelement to which the thermal resistance branch belongs, i = 1, 2…N s , N s is the number of the fan-shaped microelement; j is the number of layers of the external structure in the fan-shaped microelement, j = 1, 2, 3, λ i is the thermal conductivity, θ is the radian of the fan-shaped microelement, r jw is the outer diameter of the jth layer of the external structure, r jn is the inner diameter of the jth layer of the external structure, T ij is the thermal resistance value of the corresponding structural thermal resistance of the jth layer of the external structure in the ith fan-shaped microelement.

3. The high voltage cable whitening detection method of claim 1, wherein, The temperature is measured by a temperature sensor, and before measuring the cable surface temperature corresponding to each thermal resistance branch, the conductor temperature of the conductor and the load current value of the conductor, the method further comprises: obtaining the reading deviation of the temperature sensor; determining whether the reading deviation of the temperature sensor is less than a preset deviation range; if yes, performing the steps of measuring the cable surface temperature corresponding to each thermal resistance branch, the conductor temperature of the conductor and the load current value of the conductor.

4. The high voltage cable whitening detection method of claim 1, wherein, The calculation formula of the total heat flow of the cable is as follows: Q = I 2 R; R = R0[1 + a 20 (θ c -20)][1 + y s +y p ]; Wherein, Q is the total heat flow of the cable, I is the load current value, R is the AC resistance value of the conductor, R0, a 20 is the DC resistance of the conductor at 20°C, the temperature coefficient, θ c is the conductor temperature, y s , y p are the known skin effect factor, proximity effect factor.

5. The high voltage cable whitening detection method of claim 1, wherein, The calculation of the thermal resistance value of the white spot thermal resistance according to the thermal resistance value of the structure thermal resistance, the cable surface temperature, the conductor temperature and the total heat flow of the cable comprises: constructing a calculation linear matrix formula based on the Fourier heat conduction law and the circular thermal circuit model, the linear matrix formula comprising the structure thermal resistance, the cable surface temperature, the conductor temperature, the conductor temperature, the total heat flow of the cable and the white spot thermal resistance; substituting the numerical values of the structure thermal resistance, the cable surface temperature, the conductor temperature, the conductor temperature and the total heat flow of the cable into the linear matrix formula to obtain the thermal resistance value of the white spot thermal resistance.

6. The high voltage cable whitening detection method of claim 1, wherein, The determination of whether there is a white spot and the location of the white spot when there is a white spot according to the thermal resistance value of the white spot thermal resistance comprises: determining whether the thermal resistance value of the white spot thermal resistance is greater than 0; if no, determining that there is no white spot; if yes, determining that there is a white spot; taking the sectorial element where the white spot thermal resistance is located as the location of the white spot.

7. The high voltage cable whitening detection method according to any one of claims 1-6, characterized in that, The method further comprises: when there is a white spot, calculating the thickness of the white spot according to the thermal resistance value of the white spot thermal resistance.

8. A high voltage cable white spot detection apparatus, characterized by The structure of the cable comprises a conductor and a three-layer outer structure, the outer structure comprising, from inside to outside, an insulation layer, a buffer layer and an outer sheath, the cross section of the outer structure being annular, and the device comprising: a structure parameter acquisition module configured to acquire structure parameters of the outer structure of each layer of the cable, the structure parameters comprising an inner diameter and an outer diameter of the outer structure; a thermal circuit model construction module configured to construct a circular thermal circuit model of the cable according to the structure parameters, the circular thermal circuit model being a cross section of the cable, the cross section being divided into a plurality of sectorial microelements, each sectorial microelement comprising a plurality of thermal resistance branches extending from the conductor to the outer sheath, and each thermal resistance branch comprising a structure thermal resistance corresponding to the outer structure; at least one thermal resistance branch further comprising a white spot thermal resistance; a thermal resistance value calculation module configured to calculate, for each thermal resistance branch, a thermal resistance value of the structure thermal resistance on each thermal resistance branch according to an arc of the sectorial microelement to which the thermal resistance branch belongs and the structure parameters; a parameter measurement module configured to measure a cable surface temperature corresponding to each thermal resistance branch, a conductor temperature of the conductor and a load current value of the conductor; a cable full-line heat flow calculation module configured to calculate a cable full-line heat flow according to the conductor temperature and the load current value; a white spot thermal resistance calculation module configured to calculate a thermal resistance value of the white spot thermal resistance according to the thermal resistance value of the structure thermal resistance, the cable surface temperature, the conductor temperature and the cable full-line heat flow; a white spot qualitative analysis module configured to determine whether a white spot exists and a location of the white spot when the white spot exists according to the thermal resistance value of the white spot thermal resistance.

9. An electronic device, comprising: The electronic device comprises: at least one processor; and a memory connected to the at least one processor in communication; wherein the memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor to enable the at least one processor to execute the high-voltage cable white spot detection method of any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer readable storage medium stores computer instructions for enabling the processor to execute the high-voltage cable white spot detection method of any one of claims 1-7 when executed.

Images